CONDENSED MATTER SECTION SEMINAR on Disorder and strong electron correlations

[CM ICTP - Trieste]

CONDENSED MATTER SECTION

	
SEMINAR on

Disorder and strong electron correlations





Thursday, 15 November   -    11:00 a.m.



Seminar Room,  Main Bldg.- first floor






T. GIAMARCHI
(  University of Geneva )




"Ladders and Bose-Einstein condensation in spin systems"


Abstract

The phenomenon of Bose-Einstein condensation is a fascinating one. It 
occurs in several systems both in condensed matter and also in cold 
atomic  gases. How the interactions among the particles affect this 
transition is of course a very important question. In that respect, 
localized spin systems provide a marvelous opportunity to  study the 
BEC of strongly correlated bosons, since spins 1/2, or spin dimers can 
be  viewed as  hard core bosons. One the other hand in one dimension it 
is well known that spins behave more as fermions than as bosons.
Understanding the interplay between these two limit is thus a 
challenging  question. Recently a compound which is a good realization 
of ladders has been experimentally  studied and is a good playground to 
tackle these issues. I will thus review the above physics  of ladders 
and BEC in spin systems, and discuss the question of the dimensional 
crossover and its  experimental consequences for quantities such as the 
Nuclear Magnetic Resonance in such systems.